This thesis presents three distinct topics covering numerical simulation, experiments, and processing of data of pipe flows.

In the studies of particle migration in pipe and channel Poiseuille flows, the main goal was to extend the lift correlation in terms of slip velocity and slip angular velocity discrepancy from 2D to 3D cases, which would give a more convincing explanation for Segré-Silberberg effect. Another purpose was to study the analog and difference between the sphere migration in tube flow and the migration of a circular particle in channel flow. Two packages, ALE and DLM, were used in the numerical experiments. A method of constrained simulation was used to generate data which was processed for correlation formulas for lift, slip velocities and equilibrium position. A general procedure is established in this work and forms a link between numerical simulation and engineering practice.

Exploratory experiments were carried out for turbulent flow of sediment-laden water through a smooth pipe. This work aims at investigating the effects of particle size, shape, and mass loading on volume flux, pressure drop, friction factor and other related properties in fully-developed pressure driven pipe flows. Results for three different types of particles are presented, including Kaolinite clay, sand and glass particles. A wide range of particle concentrations and sizes were systematically studied. Arguments are presented for the critical values of Reynolds numbers at which the change of bulk flow rate switches from increase to decrease, or the modification of turbulence changes from attenuation to augmentation.

Composite friction factor correlations were derived for laminar, transition and turbulent flow in smooth and artificial rough pipes. These accurate formulas were systematically generated by smoothly connecting linear splines in log-log coordinates with a sequential logistic dose function algorithm. This method leads to a tree like structure with many branches that we call a correlation tree. Particularly, an explicit empirical formula is proposed for describing the Nikuradse's data for smooth, effectively smooth and rough pipes. Our correlation formulas are not restricted to certain ranges of Reynolds number but instead apply uniformly to all the experimental data for which data is available.